Field of the Various Embodiments
The various embodiments relate generally to acoustics technology and, more specifically, to techniques for optimizing the polarities of audio input channels.
Description of the Related Art
Oftentimes, separate audio signals, known as “channels,” are combined to create a cohesive audio mix—one or more composite signals that produce a desired listening experience for the audience. Various techniques and equipment (e.g., mixing consoles, digital audio workstations, etc.) enable mixing engineers to efficiently create customized audio mixes. For example, a mixing engineer may use a mixing console to dynamically design an audio mix of a performance in real-time (i.e., as the performance occurs) based on audio input channels received by the mixing console. In general, as part of designing the audio mix, the mixing engineer may configure the mixing console to perform one or more compensation operations, such as gain, polarity inversion, stereo panning, equalization, and the like. Each of these compensation operations modifies the contributions of one or more of the audio input channels to the audio mix in an attempt to generate a particular listening experience for the audience.
In particular, because audio input channels may combine destructively or constructively, inverting the polarity of one audio input channel (i.e., flipping the phase of the audio input channel by 180 degrees) relative to another audio input channel may significantly impact the listening experience for the audience. As is well-known, when two audio input channels combine destructively, the contributions of each of the two audio input channels to the audio mix are attenuated. Such attenuation is often perceived by listeners as “thin” sound and is particularly noticeable at relatively lower frequencies (i.e., bass frequencies). To avoid such sound degradation and improve the listening experience for the audience, many mixing engineers use a trial-and-error approach in determining whether to invert the polarity of each of the audio input channels.
With trial-and-error, the mixing engineer typically first sets the polarities of the audio input channels to an “A” set of values. The mixing engineer then auditions the “A” audio mix—subjectively assessing the quality of the “A” listening experience. Next, the mixing engineer sets the polarities of the audio input channels to a “B” set of values, usually by flipping the polarity of just one channel. The mixing engineer then auditions the “B” audio mix and compares the quality of the “B” listening experience to the quality of the “A” listening experience. If the mixing engineer believes that the “A” listening experience is superior, then the mixing engineer restores the polarities of the audio input channels to the “A” set of values. The mixing engineer continues in this same manner throughout the performance, “AB-ing” the polarities of different audio input channels in a more or less ad-hoc basis.
One problem with the above approach is that listeners are unnecessarily exposed to sound variations, especially periods of weak bass, throughout the performance. More specifically, each time the mixing engineer auditions new polarities of the audio input channels, the listeners also—undesirably—“audition” the new polarities of the audio input channels. For example, if the mixing engineer auditions a combination of polarities of the audio input channels that cause the contributions of each of two bass guitars to combine destructively, then the audience would be exposed to a thin-sounding listening experience with little or no contribution from the bass guitars for the duration of the audition.
Further, because the number of combinations for the polarities of N audio input channels is 2^(N−1) (e.g., for 32 audio input channels, there are 2,147,483,648 possible polarity combinations), a comprehensive trial-and-error approach is prohibitively time-consuming and tedious for most performances. Notably, the auditioning may take several seconds to listen to, thereby limiting the effectiveness of this style of audio mixing irrespective of whether the mixing engineer is performing the mixing operations live or off-line (i.e., in an audio studio) without an audience. Finally, because comparing the “A” and “B” listening experiences is necessarily subjective and dependent on the skill of the mixing engineer, the selected polarities of the audio input channels for the ultimate audio mix may be suboptimal.
As the foregoing illustrates, more effective techniques for optimizing the polarities of audio input channels would be useful.